package org.smart4j.chapter2.helper;

import org.apache.commons.dbcp2.BasicDataSource;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;
import org.apache.commons.dbutils.handlers.MapListHandler;
import org.slf4j.LoggerFactory;
import org.smart4j.chapter2.util.CollectionUtil;
import org.smart4j.chapter2.util.PropsUtil;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Properties;

/**
 * Created by shangjun on 2017-8-24.
 */
public final class DatabaseHelper {
    private static final org.slf4j.Logger LOGGER = LoggerFactory.getLogger(DatabaseHelper.class);
    private static final String DRIVER;
    private static final String URL;
    private static final String USERNAME;
    private static final String PASSWORD;
    //DBUtils中的工具类
    private static final QueryRunner QUERY_RUNNER = new QueryRunner();
    //使用Threadlocal来获取Connection
    private static final ThreadLocal<Connection> CONNECTION_HOLDER = new ThreadLocal<Connection>();
    //使用dbcp作为数据源
    private static final BasicDataSource DATA_SOURCE = new BasicDataSource();
        /*
        获得config.properties配置文件中的信息
         */
    static{
        Properties conf = PropsUtil.loadProps("config.properties");
        DRIVER = conf.getProperty("jdbc.driver");
        URL = conf.getProperty("jdbc.url");
        USERNAME = conf.getProperty("jdbc.username");
        PASSWORD = conf.getProperty("jdbc.password");

        DATA_SOURCE.setDriverClassName(DRIVER);
        DATA_SOURCE.setUrl(URL);
        DATA_SOURCE.setUsername(USERNAME);
        DATA_SOURCE.setPassword(PASSWORD);
        try {
            Class.forName(DRIVER);
        } catch (ClassNotFoundException e) {
            LOGGER.error("can not load jdbc driver",e);
        }
    }

        /*
        开启并返回数据库连接
        开始从ThreadLocal获取连接,如果获取不到就通过DriverManger创建一个conn,最后再把创建的这个连接放入ThreadLocal中
         */
    public static Connection getConnection(){
        Connection conn = CONNECTION_HOLDER.get();
        if (conn==null){
            try {
                conn = DATA_SOURCE.getConnection();
            }catch(SQLException e){
                LOGGER.error("can not get DATABASE connection",e);
                throw new RuntimeException(e);
            }finally {
                CONNECTION_HOLDER.set(conn);
            }
        }
        return conn;
    }

        /*
        关闭指定的数据库连接
         */
    public static void closeConnection(){
        Connection conn = CONNECTION_HOLDER.get();
        if (conn!=null){
            try {
                conn.close();
            } catch (SQLException e) {
                LOGGER.error("close Connection failure",e);
                throw new RuntimeException(e);
            }finally {
                CONNECTION_HOLDER.remove();
            }
        }
    }
        /*
        查询实体用户列表
         */
    public static<T> List<T> queryEntityList(Class<T> entityClass,String sql,Object... params){
        List<T> entityList = null;
        try {
            Connection conn = getConnection();
            entityList = QUERY_RUNNER.query(conn,sql,new BeanListHandler<T>(entityClass),params);
        } catch (SQLException e) {
            LOGGER.error("query entity list failure",e);
            throw new RuntimeException(e);
        }finally {
            closeConnection();
        }
        return entityList;
    }
        /*
        查询单个实体对象
         */
    public static<T> T queryEntity(Class<T> entityClass,String sql,Object...params){
        T entity;
        try {
            Connection conn = getConnection();
            entity = QUERY_RUNNER.query(conn,sql,new BeanHandler<T>(entityClass),params);
        } catch (SQLException e) {
            LOGGER.error("query entity failure",e);
            throw new RuntimeException(e);
        } finally {
            closeConnection();
        }
        return entity;
    }

    /*
    执行查询语句
     */
    public static List<Map<String,Object>> executeQuery(String sql,Object...params){
        List<Map<String,Object>> result;
        try {
            Connection conn = getConnection();
            result = QUERY_RUNNER.query(conn,sql,new MapListHandler(),params);
        } catch (SQLException e) {
            LOGGER.error("execute query failure",e);
            throw new RuntimeException(e);
        }
        return result;
    }
    /*
    执行更新语句,执行完毕后返回受影响的行数
     */
    public static int executeUpdate(String sql,Object...params){
        int rows = 0;
        try {
            Connection conn = getConnection();
            QUERY_RUNNER.update(conn,sql,params);
        } catch (SQLException e) {
            LOGGER.error("execute update failure",e);
            throw new RuntimeException(e);
        }finally {
            closeConnection();
        }
        return rows;
    }

    public static<T> boolean insertEntity(Class<T> entityClass,Map<String,Object> filedMap){
        if (CollectionUtil.isEmpty(filedMap)){
            LOGGER.error("can not insert entity:filedMap is empty");
            return false;
        }

        String sql = "INSERT INTO "+getTableName(entityClass);
        StringBuilder columns = new StringBuilder("(");
        StringBuilder values = new StringBuilder("(");
        for (String filedName : filedMap.keySet()){
            columns.append(filedName).append(",");
            values.append("?, ");
        }
        columns.replace(columns.lastIndexOf(", "),columns.length(),",");
        values.replace(values.lastIndexOf(", "),values.length(),")");
        sql += columns + "VALUES" + values;
        Object[] params=filedMap.values().toArray();
        return executeUpdate(sql,params) == 1;
    }
    
    /*
    更新实体
     */
    public static <T> boolean updateEntity(Class<T> entityClass,Long id,Map<String,Object> fieldMap){
        if (CollectionUtil.isEmpty(fieldMap)){
            LOGGER.error("can not update entity:filedMap is empty ");
            return false;
        }
        String sql = "UPDATE " + getTableName(entityClass) + " SET";
        StringBuilder columns = new StringBuilder();
        for (String fieldname:fieldMap.keySet()
             ) {
            columns.append(fieldname).append("=?, ");
        }
        sql += columns.substring(0, columns.lastIndexOf(", ")) + " WHERE id = ?";

        List<Object> paramList = new ArrayList<Object>();
        paramList.addAll(fieldMap.values());
        paramList.add(id);
        Object[] params = paramList.toArray();

        return executeUpdate(sql, params) == 1;
    }
    /*
    删除实体
     */
    public static <T> boolean deleteEntity(Class<T> entityClass, long id) {
        String sql = "DELETE FROM " + getTableName(entityClass) + " WHERE id = ?";
        return executeUpdate(sql, id) == 1;
    }
    /*
    执行sql文件
     */
    public static void executeSqlFile(String filePath) {
        InputStream is = Thread.currentThread().getContextClassLoader().getResourceAsStream(filePath);
        BufferedReader reader = new BufferedReader(new InputStreamReader(is));
        try {
            String sql;
            while ((sql = reader.readLine()) != null) {
                executeUpdate(sql);
            }
        } catch (Exception e) {
            LOGGER.error("execute sql file failure", e);
            throw new RuntimeException(e);
        }
    }


    private static <T> String getTableName(Class<T> entityClass) {
        return entityClass.getSimpleName();
    }


}
